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Discussion Starter · #1 ·
I have been told that using a Mircoperfed screen with a DLP projector can cause rainbows and other problems to occur when the pixels line-up with the holes. Is this true and if so, is there a solution to the problem?
 

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Quote:
Originally posted by erandmckay
I have been told that using a Mircoperfed screen with a DLP projector can cause rainbows and other problems to occur when the pixels line-up with the holes. Is this true and if so, is there a solution to the problem?
erandmckay,


Rainbow effect is independent of the screen you use. It is an inherent problem with single chip DLP projectors - and all

but the most expensive DLP projectors are single chip.


The problem with perforated screens - called "moire effect" - is when you get interference fringes caused by the

interaction of the perforations with the pixels.


It is a function of the spacing of the pixels as projected on the screen. [ The size of the pixels is determined by the size of the screen. If you make your screen bigger - with a fixed number of pixels - the pixels get bigger. ]

If the size/spacing of the pixels interferes with the spacing of the perforations - you get "moire effect".


You have to have a screen bigger than a certain size [ depending on projector ] to make sure you don't have moire.

Based on your selection of projector and screen size, Stewart can tell you if you'll have problems.


Dr. Gregory Greenman

Physicist
 

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Is there an equation of some sort that would help me to figure out the size the screen would need to be? I am looking at the Sharp 9000 DLP, is there any way to know the minimum size the screen needs to be? (I'm avoiding calling Stewart as the last time I did I got bounced around for fifteen minutes from one person to another.)
 

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I think Cain answered the question above but do a search on the screens forum with the names "Sharp" and "Don Stewart". He specifically answers the question there.
 
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